Hi Italmex
I can't answer your question about the electronics. I don't know how old these machines are and I don't know how reliable they are likely to be or how expensive it would be to get them fixed. So I can't really help you by answering your actual question.
However I just wanted to say that they do look like fantastic machines. I notice that the vendor is selling them with a 90-day guarantee, plus you are going to view them in person before buying. I can't see the dryer's power in kW, but with its 220-Volt 30-Amp supply it can be presumed to be pretty powerful and should dry quickly and its moisture sensors should be accurate. Should be a fantastic dryer. The ad says the washer is only 110 Volts but I have read the instructions on Miele's Mexican website and I see that it can still reach 70 ℃ when required, which should be perfectly adequate. I notice the Mexican instructions follow the USA system of stating spin speeds as low, medium, high, maximum rather than the European system of stating them in RPM. So I would be interested to know the machine's spin speed.
If you can afford to take a gamble with the money, then they could turn out to be a wonderful purchase. Let us know what you decide. Hopefully other members can comment with more specific things to check with these models. I am not familiar with these particular models myself. Good luck!